The present invention relates to a turbine flowmeter having an impeller wheel consisting of a hub with vanes attached whereby the wheel is rotatably mounted between a fixed hub located upstream of it and a fixed hub located downstream of it so that it can rotate and move in an axial direction.
Fluid flowing through a turbine flowmeter sets the impeller wheel in rotation. At the same time, the flowing of the liquid medium causes a hydrodynamic axial thrust to act on the impeller wheel in the direction of liquid flow and that thrust exerts a load on the thrust bearing on the downstream side of the impeller wheel, thereby causing wear which has a detrimental effect on the service life of this bearing.
To prevent or reduce this wear, the axial thrust acting on the impeller wheel is compensated for by providing the turbine flowmeter with mechanisms which place the wheel in an axial floating state. Examples of such mechanisms are known from EP 0 076 189 B1 and DE 41 05 840 A1. These and also other state-of-the-art mechanisms for relieving the axial thrust on the impeller wheel bearing(s) are relatively complicated in their construction.